On Mon, Jul 23, 2018 at 10:13:36AM -0700, Guenter Roeck wrote: > On Mon, Jul 23, 2018 at 07:48:57PM +0300, Anton Vasilyev wrote: > > static struct ro_vpd and rw_vpd are initialized by vpd_sections_init() > > in vpd_probe() based on header's ro and rw sizes. > > In vpd_remove() vpd_section_destroy() performs deinitialization based > > on enabled flag, which is set to true by vpd_sections_init(). > > This leads to call of vpd_section_destroy() on already destroyed section > > for probe-release-probe-release sequence if first probe performs > > ro_vpd initialization and second probe does not initialize it. > > > > I am not sure if the situation described can be seen in the first place. > The second probe would only not perform ro_vpd initialization if it fails > prior to that, ie if it fails to allocate memory or if there is a > consistency problem. In that case the remove function would not be called. > > However, there is a problem in the code: A partially failed probe will > leave the system in inconsistent state. Example: ro section initializes, > rw section fails to initialize. The probe will fail, but the ro section > will not be destroyed, its sysfs attributes still exist, and its memory > is still mapped. It would make more sense to fix _that_ problem. > Essentially, vpd_sections_init() should clean up after itself after it > fails to initialize a section. > > Note that I am not convinced that the "enabled" flag is needed in the first > place. It is only relevant if vpd_section_destroy() is called, which only > happens from the remove function. The remove function is only called if the > probe function succeeded. In that case it is always set for both sections.
The problem will happen if coreboot memory changes between 2 probes so that header.ro_size is not 0 on the first pass and is 0 on the second pass. Not quite likely to ever happen in real life, but resetting a flag is pretty cheap to not do it. Thanks. -- Dmitry
